X-ray apparatus



Oct. 8, 1940. R, 1:2l MACHLETT 2,216,887

' x-RAY APPARATUS Filed Nov. 17, 193s s sheets-sheet 1 ATTORNEYS Oct. 8, 1940. R. n. M ACHLETT X-RAY APPARATUS Fiied Nov. 17, v195s 5 Sheets-Sheet 2 Oct. 8, 1940. R. R. MIACHLETT x-'MY APPARATUS Filed Nov. 17, 1938 5 Sheets-Sheet 3 his aan@ oct'. 8f, 1940 i 2,216,887`

l UNITED STATES intr-slurI OFFICE y X-RAY APPARATUS Raymond R. Machlett, Riversde,'(lonn.,lassignor to Machlett Laboratories Incorporated, Springdale, Conn., a corporation of Connecticut Application November 17, 1938, Serial No. 240,965

15 Claims. (Cl. Z50-89) This invention relates to X-ray apparatus of ls-Iight and compact andalso of low cost of manthe type adapted for heavy duty use in fine detail ufacture, The new device includes an X-ray tube radiography and provided with an X-ray tube in which the target is a fiat disc rotating on the in which the target surface of the anode is caused longitudinal aXls of the tube, and the use of such to move relatively to the electron stream during a fiat disc makes possible important economies operation. More particularly, the invention is both in the production of the target and also in concerned with a novel shockproof radiographic the construction and installation of the cathode.

, apparatus of the type referred to, which is of Since the target is iiat and the useful X-ray beam vsmall size and light weight so that it is easy to must be taken off at a suitable angle to obtain handle and may be conveniently installed in exoptimum conditions with reference to the focal isting equipment. spot, the tube is mounted within the housing at In present radiographic equipment employing an angle to the longitudinal axis thereof and rotating anode tubes, the tube ordinarily used with this arrangementrthe housing maybe sup- CII contains a rotor cylinder mounted on bearings ported in the usual way with its longitudinal axis on a shank sealed through one end of the tube horizontal so that the angular location of the envelope, the cylinder being rotated during opertube does-not lead to errors on the part of the ation by they action of the eld produced by a Operator. The housing which is shockproof and stator winding surrounding that portion of the ryproof'contains a dielectric fluid in which the tube containing the cylinder. The anode is tube and its connections are immersed,-a.nd since mounted on the inner end of the cylinder or vthe tube is relatively short `und mounted anguforms apart thereof, and its target faceis conical larlv, the overall length of the housing is subor frusto-ccnical with its axis constituting a pro- Stantially less ythan that of housings used in cerlongation of the axis of the shankn The cathode tain prior apparatusis mounted at the other end of the envelope and In addition t0 those mentioned above, the new it includes one or more incandescent filaments apparatus includes numerous other novel feelying offset from the axis of rotation of the target tures Which Will be Pointed out in the detailed de- 'face and directing an electron stream against scription to follow when considered in connection the face. In shockproof equipment containing With the accompanying drawings. In these .such tubes, the tube lies horizontally in a housingv drawingshaving a window and the position of the tube is Fig-1 is a longitudinal Sectional View of the 30 such that the useful X-rays leaving the conical new apparatus showing the tube in side elevasurface i of the target pass out'y through the tion; v l l window, f ,l Figs. 2 and 3 are sectional views on the lines Such equipment as now made is objectionable 2--2 and 34-3, respectively, 0f Fig. 1; y

in that the tubes used are of considerable length, Fig- 4 isa tol) Plon View 0f the apparatus With 35` and since they lie horizontally in the housings, Parts shown in Section;

the latt" r have an overall length substantially Figs. 5 and 6 are sectional views taken on the greater" han that of the tubes so thatv the aplines 5--5 and 5 5, respectively, of Fg- 4; paratus is bulky and diicult to manipulate. Fig. 'l is a longitudinal sectional view of the Also, such prior tubes are expensive to inanufac new tube;

ture because of the dlilicult and laborious opera-k Fig- 8 is a View 0f the rotor Cylinder in side' ele- 40 tion of accurately grinding .the conical or frustovation; 4 conical 'target face of the anode, and the cathode Fig- 9 is a Sectional View 0n the line 9-9 of laments must be exactly placed in the envelope Fig-3;

with reference to the target face so that the focal Flg- 10 is a longitudinal' Sectional VGW through areas will be at the desired locations.- The posithe cathode and a part of the target, the section tioning of the target face and cathode relative being taken on the line lll-I0 of Fig; 11; and

to one another is particularly difficult in such Fig-'1 1 is a Sectional vieW on the line lI-Il of tubes when two filaments are employed and the Flg- '10. y operation requires careful and exact Workman- Referring to the drawings, the apparatus in the ship.v form illustrated includes a housing generally The present invention is, accordingly, directed "designated 20, which is of suitable metal and to the provision. of a shockproof radiographic grounded. The housing preferably consists of an device from which the objectionable features of upper part 2| and a removable bottom 22 and the prior equipment are absent, and the new unit the upper part and bottom have peripheral anges ings in one flange and into the other.

23, 24, respectively, meeting in a horizontal plane. A gasket is interposed between the flanges to make the housing liquid tight andthe two parts ofthe housing are connected together in any suitable way, as by screws 26 threaded through open- 'I'he housing is rayproofed by being provided with a lead lining 21 throughout those portions of the two parts of the housing through which X-rays might otherwise pass, and the bottom of the housing is formed with an opening closed by a window 28, which is made of a suitable material, such as a phenolic condensation product. The housing,.as illustrated, is symmetrical about a plane normal to the longitudinal axis of the housing and passing through the window, this arrangement facilitating the use of the apparatus.

The window is secured in position in any suitable way, and, for this purpose, may be provided with a ange 28a which is held against a gasket 2 9 in a channel in the bottom of the housing by means of a threaded ring 38. The inner wall 28h ofthe window lies at an angle to the longitudinal axis of the housing and parallel to the adjacent portion of the envelope of the tube within the housing so that the X-rays'from' the tube pass through a layer of dielectric iiuid of substantially uniform thickness. Attached to the bottom of. the housing in alignment with the window is the usual adapter cone 3 i.

An X-ray tube which includes an envelope 32 having an enlarged central section 33 and reduced neck portion 34, 35, is mounted in the housing by supporting means secured to the upper part of the housing. At one end, the support comprises a bracket 36 o f suitable material, such as a canvas base synthetic resin, which is secured to a metal bracket 31 which is attached to a suitable boss 38 projecting downwardly from the inner wall of the top member of the housing. The free end of the bracket 36 is forked and provided withV openings at the end of each leg. The neck 34 of the tube is seated in the bracket against a cushion 39 of suitable material, such as cork, and is held in place by a lashing which may consist of strands of linen cord or the like.

The other end neck 35 of the tube is supported in a bracket 4l which is made of a material similar to that used for the bracket 36 and is supported on lug's 42 projecting inwardly from the inner wall of the upper part of the housing. The bracket 4i is attached to the lugs by screws 43 passing through slots in the bracket and into the lugs so that the vertical position of the bracket may be adjusted as desired. The tube neck 35 is maintained in position within the bracket by means of a crossbar 44, attached to the bracket from beneath, and layers of cushioning material, such as cork, are interposed between the neck and the surfaces of the bracket and crossbar.

Extending rearwardly from the upper part of the housing, near the ends thereof, are integral necks 46, each of which contains an insulating thimble 41. Each insulator is provided with a peripheral ilange held against a gasket 48 in a channel at the open end of the neck by a ring 49 threaded into the channel. The end of a high l and these terminals are connected'by wires 55 to.

tension cable 50a, 58h 'enters each insulator bare ends of which enter sockets in terminals 54 projecting through the end of the insulator 41,

the terminals at the cathode end of the X-ray tube. The cable 58h contains a single conductor, the end of which enters a socket in a terminal 56 which projects through the end of the insulator. A conductor 51 is connected at one end to terminal 56 and has its other end held beneath the head of a screw 58 threaded into a shank 59 which enters the end of the neck 35, and lies with its axis coincident with that of the envelope.

The housing 20 contains a quantity of dielectricv liquid, such as oil, in which the tube and its connections are immersed, and to permit expansion of the oil when it is heated during operation, the upper part of the housing is provided with chambers 60 opening into the interior of the housing and containing collapsible bellows 6I. Between4 the chambers 68 is a chamber 62 in the inner wall 63 of which are mounted three terminals 64. Conductors 65 lead from these terminals to terminals in a receptacle 66 mounted in the bottom wall of chamber" 62, and current is supplied to the receptacle terminals in the usual way from a three wire cable 61 through the prongs of a plug 68 at the end of the cable. The inner ends of the terminals 64 are connected by suitable conductors (not shown) to windings 69 mounted in slots n a laminated core 18, the windings and core forming a stator through the middle of which ex-- tends the neck 35 of the tube. The stator is mounted in position by means of a bracket 1I, secured to the top of the core and toa boss 12 projecting downwardly from the inne'r wall of the upper part of the housing.

. The tube envelop'e 32 consisting of the central enlarged portion 33 and necks 34, 35 is symmetrical about alongitudinal axis -passing through the necks, and the necks have re-entrant 'end portions. The neck 35 is of less diameter and greater length than the neck 34 and the shank 59 entering the neck 35 is sealed to the re-entrant end portion thereof by a tubular metallic seal 13, the shank being provided with a portion 14 of enlarged diameter just inside the seal.

A rotor cylinder 15 of ferromagnetic material is mounted on the portion of the shank 59 within the tube for rotation, and for this purpose, roller bearings are interposed between the cylinder and shank, the bearings being of a suitable alloy which will withstand the degassing treatment necessary. The bearing near the outer end of the cylinder comprises a split inner race 16 through which the shank passes, the race being in con-l tact with the inner face of the enlarged portion 14 of the shank. The halls 11 lie between the inner race and an outer'race 18 which is in contact with the inner surface of the cylinder 15, thev race being held against outward movement relative to the cylinder by suitable means, such as one or more set screws 19 threaded through the wall oir the cylinder. The inner ball bearing also consists of a split inner race 88 in contact with the outer surface of shank 59, balls 8l, and an outer race 83 in contact with the inner surface of the cylinder. I'he inner races of the ball bearings are kept at the proper spacing by a sleeve 84 surrounding the shank, and the outer races are similarly spaced by a sleeve 85 lying against the inner surface of the cylinder. 'I'he inner race 80 is held against moving oif the end of the shank by the head of a screw .86 threaded into the end of the shank, and the outer race 83 is kept from moving out of the cylinder by a frusto-conical member 81 secured to the end of the cylinder and projecting inwardly to overlie the end of the race.

A hollow stem 88 of a metal of low heat con-f ductivity, such as molybdenum, is secured .to the member 81 with its axis forming aprolongation of the axis of the shank'59, and the stem 88 is provided with a peripheral boss 89 having a flange i which is preferably interrupted, so that the flange During the operation of the tube, the target disc is rotated on the longitudinal axis of the tube by the action of the field produced by the stator on a rotor consisting of the ferromagnetic cylinder Y 'l5 and a copper squirrel cage embedded therein.

The squirrel cage which is ofthe same general construction as those used in induction motors,

i consists of end rings 94 connected by longitudinal bars 95, the metal forming the rings and bars being introduced into suitable channels in the surface of cylinder 'I5 by vacuum casting. lThe squirrel cage portion of the rotor structure lies .within the stator, as shown in Fig. 7, and a sleeve 96 of suitable insulating material is interposed between the stator and the neck 35 of the tube, a layer of cushioning material 91, suchI as impregnated cambric, being interposed between the sleeve 95 and the tube envelope.

Projecting inwardly through the re-entrant end portion of the neck 34 of the tube is a tube 98 through'the outerend of which are sealed the conductors 55.- Thetube 93 projects into the en- 'velope beyond the re-entrant end portion of the neck 34 and on the inner end of the-tube is mounted a slotted metal sleeve 99 which is held in place by circular straps |00. The ground cond uctcr |0| is" connected electrically to the sleeve 99.

In the inner end of the` sleeve is mounted a block |02 to which is attached anarm |03 and `attached to the end of the arm is a block |04 having one or more semi-cylindrical channels |05 in its outer facelin which laments are mounted. In the construction shown, there are two such filaments |06a, |061) of different lengths and each filament is mounted between two wires |01a, |0`|b extending through passages inthe block, |04 and corresponding openings through the arm |03. One wire |0'|a for each filament passes through an insulating bushing' |08 in the arm |03 and is connected to one of theconductors 55, the por'- tion of the conductor from the bushing Ato the seal at the end of the tube 98 being provided with insulation. The conductorsv 55 pass out through an opening in the sleeve 99 and enter a cup |89 attached to the rear facel of the arm |03, within which they are connected to the wires |01a. The other wire |01b makes contact with the arm |03 in its opening therethrough and is connected to.

l ground through the arm, the sleeve 99, and the ground conductors 99, 55.

The filaments arein the usual coiled form and lie with their axes parallel to the face of the target disc A9 In order that the electron streams from the two `laxnents may be directed against electron streams from the filaments are focused by the Walls of the semi-cylindrical recesses |05 to strike thev same area onthe target, asl indicated in Fig. 10.

f In some instances, it may be desirable to provide a getter withinthe tube and for this purpose,

a conductor H8 may be mounted within the tube 98 and connected to the conductor 99 leading to ground. That portion of the conductor H9 lying within the tube is coated with gettering material y and is connected to a conductor 55 sealed through the end of the tube 99 and supplied with current through a suitable connection, not shown.

In prior apparatus provided with an Xray tube with a. rotating target, the target surface has been formed with an inclination to the central ray of the useful beam in order vthat the elongated l practise to mount the anode to rotate on the longitudinal axis of the tube and to support the tube with that axis horizontal. Under those conditions, an inclination of the target surface at an angle of about 15 to the central ray is obtained by forming the surface at an angle of about 75 to the tube axis. 'I'he desired foreshortening effect thus depends on accurate formation of the target surfaceV and Aequally accurateA positioning of the cathode laments with reference to the surface. Similarly, in the case of a two filament tube, the filaments must be accurately mountedk in proper angular relation to one another, in order that their focal spots on the inclined target surface Will lie parallel and in similar relation to the external`object. The difllculties involved in producing target surfaces of tungsten inclined at the necessary angle and in positioning the filaments relative to the surface and to one anotherl add materially to the cost of productionof such tubes. In the present apparatus, the use of the flat target disc affords important economies in cost of manufacture in that the anode may be made- 'their axes parallel ,and the formation of their support to obtain the desired focusing is a relatively simple'machining operation.

Another advantage obtained by the use of a flat disc target rotating in a plane at right angles to the tube axis is that the possibility of stray electrons passing from the target face into that part of the tube lying behind the target is greatly l reduced. With the target face at aninclination to the axis of rotation, the range of travel of such electrons is much greater than in the case of the flat disc and the danger of injury being done by such electrons is correspondingly increased.

Since the new tube has a flat target lying at right angles to the tube axis and the target surface should be at an angle of from 15 to 25 to the central beam to obtain the desired foreshort- `ening. of the focal spot, the tube itself is mounted in the housing at an appropriate angle relative to thelongitudinal axis thereof. With this arrangement, the housing may be supported, as is usual,

operator does not have to consider the angular position of the tube to the horizontal. -The particular adjustable mounting provided makes it easy -to place the tube in correct position, and the angular relation of the tube to the housing makes it possible tb make the housing somewhat shorter in overall length than would be possible if the tube axis and that of the housing were parallel.

In the apparatus described, the housing encloses only the tube and its associated parts but for some purposes, it may be desirable to employ a larger housing containing both the tube and a trans` former, and in that case, the tube is again mounted-so that the target face makes the desired angle to the central beam. In both constructions, the tube is preferably positioned so that the electron stream from the cathode strikes the ytarget surface on the same side of the axis of rotation as that on whichthe object to be radio- A ing through the window, an X-ray tube Within the housing having an envelope containing an anode mounted for rotation relative to the envelope on the longitudinal axis of the tube and having a substantially fiat Iface and a cathode directing an electron stream against said face of the anode at one side of the axis of rotation thereof, and means for supporting the tube within the housing in such position of inclination relative to the longitudinal axis of the housing that X-rays from said faceof the anode will pass through the Window.

2. An X-ray apparatus which comprises a rayproof housing having' a window, an X-ray tube within the housing containing a rotary anode having a target face lying substantially in a plane and a cathode directing an electron stream against the target face at one side of the axis of rotation thereof, and means for supporting the tube within the housing with the longitu-y dinal axis of the tube inclined to the longitudinal axis of the, housing and\in such position that X-rays from the target face will pass through the Window. f

3. An, X-ray apparatus whichjl comprises a housing having a window, an X-ray tube Within the housing containing an anode rotatable on the longitudinal axis of the tube and having a substantially fiat target face and a cathode directing ,"an electron stream against the target face at one side of the axis of rotation of the anode, and means for supporting the tube within the housing with the plane of rotation of the' target face at an oblique angle to the longitudinal axis of the housing and in such position that X-rays therefrom will pass outwardly through the window.

4. An X-ray apparatus which comprises a housing having a window,` the housing being symmetrical with respect to a transverse plane passing through the window, an X-ray tube within the housing having an envelope containing an anode having a fiat target face and mounted for rotationrelative to the envelope on the longitudinal axis of the tube and a cathode offset from said axis and directing an electron stream against said target face, and means for sup-u porting the tube within the housing in such 2,216,887 with its longitudinal axis horizntal, so that theV position of inclination relative to the longitudinal axis of the housing that X-rays from the target face will pass through the window.

5. An X-ray apparatus which comprises a housing containing a dielectric medium and having a window, an X-ray tube within the housing immersed in the dielectric medium, the tube containing a rotary anode having a substantially fiat target face and a cathode directing an electron stream against the target face at one side of the axis of rotation thereof, and means for supporting the tube within the housing with its longitudinal axis at such an oblique angle to the longitudinal axis of the housing that X-rays from theetarget face will pass through the window, the portion of the window adjacent the surface of the tube lying substantially parallel to that surface.

e 6. An X-ray apparatus which comprises a housing containing a liquiddielectric medium and provided with a window in one wall thereof, an X-ray tube within the housing lying with its longitudinal axis at an angle to the longitudinal axis of the housing, the tube being immersed in the medium and containing an anode from which X-rays pass out of the housing throughthe window, and means for supporting the tube within the housrlig, the portion of the window adjacent the rface of the tube envelopeV lying spaced a substaxitially uniform distance therefrom to provide a lm lof the liquid through which the rays pass which is of substantially uniform thickness.

'7. An X-ray apparatus which comprises an elongated housing having an upper part and a removable bottom therefor provided with a Window, the upper part and bottom having meeting edges extending lengthwise of thehousing, an X-ray tube Within the housing, andmeans for supporting the tube from the upper part of thek housing in such position that X-rays from the tubewill pass through the window, the tube -being exposed from end to end on yremoval of the bottom of the housing;

8. An X-ray apparatus which comprises aA housing having an upper part and a removable bottom therefor -provided with a. window, an X-ray tube within the housing, the tube -containing a rotary anode having a substantially fiat target face and a cathode directing an electron stream against the face at one side of the axis of rotation thereof, and means attached to the-upper part of the housing for supporting the tube with the flat target iaceof the anode at such an oblique angle to the longitudinal axis of the housing that X-rays from the target face ywillpass through the window.

9. An X-ray apparatus which comprises an elongated housing made up of an upper part and a removable bottom provided with a window, the upper part and bottom having meeting edges extending lengthwise of the housing and the latter containing a dielectric liquid, an X-ray tube within the housing and immersed in the liquid, termials in the wall of; the upper part of the housing, connections from the terminals to the terminals of the tube, and means attached to the upper part of the hounsing for supporting the tube in such position that X-rays therefrom will pass through the window, the tube being exposed from end to end on removal of the bottom of the housing.

10. An X-ray apparatus which comprises an elongated housing made up of an upper part and a. removable bottom provided with a window, the

upper part and bottom having meeting edges'ex-l tending lengthwise of the-housing and the latter containing a dielectric liquid, an X-ray tube to the upper part of the housing and permitting expansion of the liquid vas the latter is heated, and means attached to the upper partiof 4the housing for supporting the tube in such position that X-rays therefrom will pass through the window, the tube being exposed from end to end,

on removal of the bottom of the housing.

11. An X-ray apparatus which comprises an elongated housing made up of an upper part and a removable bottom provided with a window, the upper part and bottom extending from end to end of the housing, an X-ray tube within the housing, the tube containing a rotatable anode and a cathode, a stator winding on the tube at the anode end, means secured to the upper part of the housing for supporting the statoi` winding, and means secured to the upper part of the housing and engaging the tube adjacent the ends thereof for supporting the tube, the removal of the bottom exposing the tube from end to end.

12. An X-ray apparatuswhich comprises a housing made up of an upper part and a removable bottom provided with a window,-the upperpart and bottom extending from end` to end of the housing, an X-ray tube Within the housing,

the tube containing a rotatable anode having a substantially flat target face and a cathode for directing an electron stream against the target face at one side of the axis of rotation of the anode, and means. secured to the upper part of ,the housing for supporting the tube with its longitudinal axis inclined to the horizontal, the cathode end of the tube being lower than .the anode endl and projecting into the bottom of the housing.

13. An X-ray apparatus which comprises a housing having a window in one Wall thereof, an X-ray tube within the housing, the. tube containing an anode rotatable on the longitudinal axis of the tube and provided With a substantially vflat target face' and a cathode eccentric to said axis and directing an electron stream against the target face at one side of the axis of rotation thereof, and means for supporting the tubewithin the housing with its longitudinal axis at an oblique angle to the longitudinal .axis of the housing such that X-rays from the target face pass through the Window.

14. An X-ray apparatus which comprises a housing having a window in one wall thereof, an X-ray tube within the housing, the tube containing a rotatable anode having a substantially flat target face and a cathode directing an electron stream against the target face at one side of the axis of rotation of the' anode, and means for supporting the` tube within the housing in such an inclined position relative to the longitudinal axis of the housing that the electron stream from the cathode strikes the target face below the axis of rotation of the anode and X-rays from thevtarget face pass through the window.

15. An X-ray apparatus which comprises a housing elongated along one axis and `having a window'in one lateral wall thereof, an X-ray tube within the housing containing an anode mounted for rotation and having a substantially at target surface lying at right angles to the axis of rotation of the anode, and a cathode for with the central ray of the X-ray beam leaving through the window in a direction normal to said axis of the housing. i

RAYMOND R. MACHLE'I'I. 

